Abstract:

A filament lamp and light irradiation type heat treatment device capable
of uniformly thermally processing the entirety of an article to be
treated has a filament lamp (100) in which coil-shaped filaments are
disposed along the tube axis within a light emitting tube (102), wherein
the filaments are electrically connected to a low-emission coil (F2'')
having a relatively smaller effective surface area and to high-emission
coils (F1'', F1'') having relatively large effective surface areas, with
the low-emission coil disposed in between in the axis of the tube
direction, and a light irradiation type heat treatment device utilizing
the filament lamp (100).

Claims:

1. A filament lamp, comprising:a light emitting tube, a coil-shaped
filament disposed extending along the tube axis in the light emitting
tube,wherein the coil-shaped filament comprises a high radiance coil
having a relatively large effective surface area which is electrically
connected to a low radiance coil having a relatively small effective
surface area at each of opposite ends of the high radiance coil in a
longitudinal direction of the light emitting tube.

2. A filament lamp, comprising:a light emitting tube,a plurality of
filaments in the interior of said light emitting tube and to which a pair
of leads are electrically connected via electrically conductive parts
disposed in a hermetically sealed portion formed on at least one end of
the light emitting tube, each filament extending along a longitudinal
axis of the light emitting tube,wherein the coil-shaped filament
comprises a low radiance coil having a relatively small effective surface
area which is disposed in a center in the tube axis direction,a high
radiance coil having a relatively large effective surface area which is
disposed at an end of the direction of the tube axis of the light
emitting tube at both sides of the low radiance coil.

3. A light irradiation type heat treatment device, comprising:a plurality
of filament lamps in which coil-shaped filaments extend inside a light
emitting tube along a longitudinal axis thereof,wherein said lamps are
disposed so as to form a surface light source,wherein, in each of the
filament lamps, the effective surface area per unit length of the
filaments disposed in an area corresponding to an outer edge zone of an
article to be treated is greater than an effective surface area per unit
length of filaments disposed in an area corresponding to a center zone of
the article to be treated.

4. The light irradiation type heat treatment device of claim 3, wherein an
external diameter of each of the filament coils disposed in the area
corresponding to the outer edge zone of the article to be treated is
larger than the external diameter of each of the filament coils disposed
in the area corresponding to the center zone of the article to be
treated.

5. The light irradiation type heat treatment device of claim 3, wherein
the pitch of each of the filament coils disposed in the area
corresponding to the outer edge zone of the article to be treated is
smaller than the pitch of each of the filament coils disposed in the area
corresponding to the center zone of the article to be treated.

6. The light irradiation type heat treatment device of claim 3, wherein
the strand diameter of each of the filament coils disposed in the area
corresponding to the outer edge zone of the article to be treated is
larger than the strand diameter of each of the filament coils disposed in
the area corresponding to the center zone of the article to be treated.

7. The light irradiation type heat treatment device of claim 3, wherein
each of the filaments disposed in the area corresponding to the outer
edge zone of the article to be treated and each of the filaments disposed
in an area corresponding to the center zone of the article to be treated
has the same effective surface area in each of the respective zones.

8. A light irradiation type heat treatment device, having:a plurality of
filament lamps, each of which comprises:a light emitting tube,a plurality
of filaments in the interior of said light emitting tube and to which a
pair of leads are electrically connected via electrically conductive
parts disposed in a hermetically sealed portion formed on at least one
end of the light emitting tube, each filament extending along a
longitudinal axis of the light emitting tube,wherein, in each of the
filament lamps, the effective surface area per unit length of the
filaments disposed in an area corresponding to an outer edge zone of an
article to be treated is greater than an effective surface area per unit
length of filaments disposed in an area corresponding to a center zone of
the article to be treated.

9. The light irradiation type heat treatment device of claim 8, wherein an
external diameter of each of the filament coils disposed in an area
corresponding to an outer edge zone of the article to be treated is
larger than the external diameter of each of the filament coils disposed
in a center zone of the article to be treated.

10. The light irradiation type heat treatment device of claim 8, wherein
the pitch of each of the filament coils disposed in the area
corresponding to the outer edge zone of the article to be treated is
smaller than the pitch of each of the filament coils disposed in the
center zone of the article to be treated.

11. The light irradiation type heat treatment device of claim 8, wherein
each of the filaments located in the area corresponding to the outer edge
zone of the article to be treated has a strand diameter that is greater
than the strand diameter of each of the filament coils disposed in the
center zone of the article to be treated.

12. A light irradiation type heat treatment device, comprising:a plurality
of filament lamps in which coil-shaped filaments extend inside a light
emitting tube along a longitudinal axis thereof,wherein said lamps are
disposed so as to form a surface light source,wherein the coil-shaped
filaments comprise a high radiance coil having a relatively large
effective surface area which is electrically connected to a low radiance
coil having a relatively small effective surface area at each of opposite
ends of the high radiance coil in a longitudinal direction of the light
emitting tube, and wherein said low radiance coil is disposed facing the
center of the article to be treated, and said high radiance coil is
disposed facing the outer edge of the article to be treated.

13. The light irradiation type heat treatment device of claim 12, wherein
an external diameter of the high radiance coil is larger than the
external diameter of the low radiance coil.

14. The light irradiation type heat treatment device of claim 12, wherein
the coil of the high radiance coil has a pitch which is smaller than the
pitch of the low radiance coil.

15. The light irradiation type heat treatment device of claim 12, wherein
the strand diameter of the high radiance coil is larger than the strand
diameter of the low radiance coil.

16. The light irradiation type heat treatment device of claim 15, wherein
each of the filaments disposed in the area corresponding to the outer
edge zone of the article to be treated and each of the filaments disposed
in an area corresponding to the center zone of the article to be treated
has the same effective surface area in each of the respective zones.

17. The light irradiation type heat treatment device of claim 12, wherein
each of the filaments disposed in the area corresponding to the outer
edge zone of the article to be treated and each of the filaments disposed
in an area corresponding to the center zone of the article to be treated
has the same effective surface area in each of the respective zones.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of Invention

[0002]This invention relates to a filament lamp and a light irradiation
type heat treatment device, and in particular, to a filament lamp and a
light irradiation type heat treatment device used to thermally process
semiconductor wafers and other articles to be treated.

[0003]2. Description of Related Art

[0004]Thermal processing is widely employed in various steps that are part
of the semiconductor manufacturing process, including film formation,
oxidation, nitriding, film stabilization, silicidation, crystallization,
and ion injection activation. In order to improve efficiency and product
quality in semiconductor manufacturing processes, rapid thermal
processing (RTP), in which the temperature of semiconductor wafers or
other articles to be treated is rapidly raised and lowered, is desirable.
Light irradiation type heat treatment devices (referred to hereafter
simply as heat treatment devices) that use light irradiation from light
sources such as incandescent lamps are widely used in RTP.

[0005]Here, when the article to be treated is a semiconductor wafer
(silicon wafer), for example, when the semiconductor wafer is heated to
at least 1050° C., non-uniformity occurs in the temperature
distribution on the semiconductor wafer. This phenomenon is referred to
as slip, or in other words, defects in crystal transition, which can
result in a defective product. Accordingly, in a case in which
semiconductor RTP is performed using a light irradiation type heat
treatment device, the heating, keeping at a high temperature and cooling
must be performed so that the temperature distribution is uniform across
the entire surface of the semiconductor wafer. In other words, in RTP,
high-precision temperature uniformity is needed for the article to be
treated.

[0006]In order to perform this rapid thermal processing, a light
irradiation type heat treatment device is employed, configured with a
plurality of filament lamps, each having a plurality of coiled filaments
of differing lengths disposed in the interior of a light emitting tube,
configured as a surface light source with the filaments corresponding to
the shape of the article to be treated.

[0007]FIG. 13 shows the configuration of a lamp unit 200 to which the
light irradiation type heat treatment device according to conventional
technology has been applied.

[0008]As shown in the drawing, in order to heat the article W to be
treated so the temperature distribution is uniform on the surface of the
article W to be treated, the electric power applied to a filament lamp
210 is adjusted so that the electric power applied to a filament F2 on
the filament lamp 210 corresponding to an edge zone Z2 peripheral to the
center of the article to be treated is greater, considering that thermal
radiation from the peripheral of the article W to be treated occurs.
Specifically, the rated power density in the filament F2 in the filament
lamp 210 disposed corresponding to the peripheral zone Z2 of the article
W to be treated is increased in relation to the rated power density in a
filament F1 of the filament lamp 210 disposed corresponding to the center
zone Z1 of the article W to be treated.

[0009]Simultaneously, each filament lamp 210 is designed so that the rated
power density of a filament 220 disposed corresponding to each zone Z1
and Z2 is identical for each zone Z1 and Z2, so the strength of the light
emitted on each zone Z1 and Z2 of the article W to be treated is uniform.
To offer an example, the lamp is designed so that each filament F2
disposed corresponding to the peripheral zone Z2 of the article W to be
treated has the same rated power density of 100 W/cm, while each filament
F1 disposed corresponding to the center zone Z1 of the article to be
treated has the same rated power density of 50 W/cm; see, for example,
JP-A-2006-279008 and corresponding US 2006/197454 A1.

[0010]However, the fact has been shown that, when a article to be treated
is thermally processed using the light irradiation type heat treatment
device described above, it is impossible to heat the silicon (Si)
substrate or other article to be treated so that the surface temperature
is uniform. In other words, the fact has been shown that when the mass
and surface area of a filament are identical per each unit of length of
each independently powered filament, in order to heat the article to be
treated uniformly, increasing the power density per unit of length of
filaments corresponding to the center zone of the article to be treated
in relation to the power density per unit of length of filaments
corresponding to the peripheral zone of the article to be treated shifts
the spectrum of the light emitted from the filaments corresponding to the
peripheral zone toward shorter wavelengths than filaments corresponding
to the center zone of the article to be treated, and the energy ratio on
the shorter wavelength side will occupy a greater portion of the overall
irradiance.

[0011]FIG. 14 shows a spectral irradiance comparison in a case in which
the total irradiance is identical (equivalent to making the power density
identical). The drawing shows that if the color temperature (in other
words, the filament surface temperature) differs even when the total
energy emitted is the same, the spectral irradiance differs for each
wavelength. The term "color temperature" here expresses the color of
light at the temperature of a black body. In a case in which filament
materials are identical (tungsten, in this example), filament surface
temperature values and color temperature values of light from the
filaments have a 1:1 correspondence. Since the relationship between
surface temperature and the color temperature of emitted light from that
surface has been calculated in advance, the color temperature of the
light may be calculated and used in place of the surface temperature of
the filament. In other words, when the mass and surface area of the
filaments per unit of length are identical, a higher power density
supplied per unit of length of the filaments raises the filament
temperature, while a lower power density per unit length of the filaments
lowers the filament temperature. With the raising and lowering of the
temperature, the phenomenon occurs of shifting toward shorter wavelengths
of the wavelength of light emitted from the filaments, as shown in FIG.
14.

[0012]FIG. 15 shows the absorbance properties (the transmittance for light
wavelength) at each wavelength for silicon (Si), gallium arsenide (GaAs),
and germanium (Ge). The vertical axis indicates transmittance (%), while
the horizontal axis shows light wavelength (μm). The illustration
shows an absorbance property when the article to be treated is silicon
(Si) exhibiting a rapid change in transmittance from 0% to 100% from 1
μm to 1.2 μm. In other words, silicon (Si) powerfully absorbs light
with a wavelength of 1 μm or less, while it transmits nearly all light
with a wavelength of over 1.1 μm.

[0013]Consequently, when filaments corresponding to the central zone of
the article to be treated have a strong irradiance for light with a
wavelength of over 1.1 μm and filaments corresponding to the
peripheral zone of the article to be treated have a strong irradiance for
a wavelength of 1 μm or less, the ratio of the power density per unit
of length of the filaments corresponding to the central zone of the
article to be treated to the power density per unit of length of the
filaments corresponding to the peripheral zone of the article to be
treated does not have a proportional relationship to the ratio of the
thermal dose of the peripheral zone to the central zone of the article to
be treated. In other words, since the wavelengths of the emitted light
differ, the central zone of the article to be treated is more weakly
heated because more light passes through and less is absorbed, while the
peripheral zone of the article to be treated heats rapidly because less
light passes through and more light is absorbed. As a result, a
temperature differential occurs between the central zone and the
peripheral zone of the article to be treated, and for this reason,
heating the article to be treated so the temperature distribution is
uniform on the surface of the article to be treated is believed
impossible.

SUMMARY OF THE INVENTION

[0014]Taking note of the problems noted above, an object of the present
invention is to provide a filament lamp and a light irradiation type heat
treatment device capable of heating the entirety of a article to be
treated uniformly.

[0015]The present invention has adopted the following means for solving
the problems noted above.

[0016]The first means is a filament lamp having a coil-shaped filament
disposed extending along the tube axis in a light emitting tube, wherein
the filament is electrically connected to a low radiance coil having a
relatively small effective surface area and to a high radiant coil having
a relatively large effective surface area, on which the low radiance coil
element is disposed on both sides in the tube axis direction.

[0017]The second means is a filament lamp in which a plurality of
filaments, to which are linked a pair of leads for supplying electric
power to said filament at both ends of the coil-shaped filament in the
interior of a light emitting tube upon which a hermetically sealed
portion is formed on at least one end, are disposed with each filament
extending along the tube axis of the light emitting tube. Each lead is
electrically connected to electrically conductive parts disposed in each
hermetically sealed portion, wherein the filament lamp comprises a low
radiance coil having a relatively small effective surface area and a high
radiance coil having a relatively large effective surface area, on which
the low radiance coil element is disposed on both sides in the tube axis
direction. A "relatively small" effective surface area here means that
the surface area is smaller than the "relatively large" effective surface
area, and vice versa. That is, the effective surface area of the low
radiance coil is smaller than the effective surface area of the high
radiance coil.

[0018]The third means is a light irradiation type heat treatment device
having a plurality of filament lamps in which coil-shaped filaments
extending along the tube axis inside a light emitting tube, are disposed
so as to comprise a surface light source, wherein the effective surface
area per unit length of the filaments in the filament lamps disposed
corresponding to the outer edge zone of the article to be treated is
greater than the effective surface area per unit length of filaments
disposed corresponding to center zone of the article to be treated.

[0019]The fourth means is a light irradiation type heat treatment device
wherein a plurality of filament lamps having a plurality of filaments, to
which are linked a pair of leads for supplying electric power to said
filament at both ends of the coil-shaped filament in the interior of a
light emitting tube upon which a hermetically sealed portion is formed on
at least one end are disposed with each filament extending along the tube
axis of the light emitting tube, wherein each lead is electrically
connected to electrically conductive parts disposed in each hermetically
sealed portion, are disposed so as to comprise a surface light source,
wherein the filament lamps comprise a low radiance coil having a
relatively small effective surface area and a high radiance coil having a
relatively large effective surface area, on which the low radiance coil
element is disposed on both sides in the tube axis direction.

[0020]The fifth means is a light irradiation type heat treatment device of
the third means or the fourth means wherein, in the filament lamps, the
external diameter of each of the filament coils disposed corresponding to
the outer edge zone of the article to be treated is smaller than the
pitch of each of the filament coils disposed corresponding to the center
zone of the article to be treated.

[0021]The sixth means is a light irradiation type heat treatment device of
the third means or the fourth means, wherein in the filament lamps the
pitch of each of the filament coils disposed corresponding to the outer
edge zone of the article to be treated is smaller than the pitch of each
of the filament coils disposed corresponding to the center zone of the
article to be treated.

[0022]The seventh means is the light irradiation type heat treatment
device of the third means or the fourth means, wherein in the filament
lamps the strand diameter of each of the filaments disposed corresponding
to the outer edge zone of the article to be treated is greater than the
strand diameter of each of the filament coils disposed corresponding to
the center zone of the article to be treated.

[0023]The eighth means is a light irradiation type heat treatment device
upon which a plurality of the filaments lamps described in the first
means are disposed so as to comprise a surface light source, wherein said
low radiance coil is disposed facing the center of the article to be
treated, and said high radiance coil is disposed facing the outer edge of
the article to be treated.

[0024]The ninth means is the light irradiation type heat treatment device
of the eighth means, wherein the coil external diameter of the high
radiance coil is larger than the coil external diameter of the low
radiance coil.

[0025]The tenth means is the light irradiation type heat treatment device
of the eighth means, wherein the coil pitch of the high radiance coil is
smaller than the coil pitch of the low radiance coil.

[0026]The eleventh means is the light irradiation type heat treatment
device of the eighth means, wherein the strand diameter of the high
radiance coil is larger than the strand diameter of the low radiance
coil.

[0027]The twelfth means is the light irradiation type heat treatment
device of any one of the third means through the eleventh means, wherein
each of the filaments disposed in the area corresponding to the outer
edge zone of the article to be treated and each of the filaments disposed
in the area corresponding to the center zone of the article to be treated
has the same effective surface area in each of the respective zones.

[0028]According to the invention, it is possible to realize a filament
lamp capable of heating an article to be treated so the temperature
distribution is uniform on the entire surface of the article to be
treated because, in a case in which the color temperature of the low
radiance coil and the high radiance coil is kept constant, it is possible
to increase the emission intensity from the high radiance coil in
relation to the emission intensity from the low radiance coil, and it is
possible to make the shape of the emission spectrum of the low radiance
coil identical to the shape of the emission spectrum of the high radiance
coil.

[0029]In addition, according to the invention, it is possible to realize a
filament lamp capable of heating an article to be treated so the
temperature distribution is uniform on the entire surface of the article
to be treated because, in a case in which the color temperature of the
low radiance coil (low radiance filaments) and the high radiance coil
(high radiance filaments) is kept constant, it is possible to increase
the emission intensity from the filaments with a larger effective surface
area per unit of filament length in relation to the emission intensity
from the filaments with a smaller effective surface area per unit of
filament length, and it is possible to make the radiant spectral shapes
of both filaments identical.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]FIG. 1 is a front sectional view showing the configuration of a
light irradiation type heat treatment device according to the first
embodiment.

[0031]FIG. 2 is a view from above of the configuration of the lamp unit
shown in FIG. 1.

[0032]FIG. 3 is a perspective view showing the configuration of the
filament lamp shown in FIG. 2.

[0033]FIGS. 4(a) & 4(b) are schematic sectional views extending along the
tube axis plane of a filament strand in the filament formed by winding
into the coil shape shown in FIG. 3.

[0034]FIG. 5 is a schematic sectional view extending along the tube axis
plane of the filaments formed by winding into the coil shape shown in
FIG. 2.

[0035]FIG. 6 is a schematic sectional view extending along the tube axis
plane of the filaments formed by winding into the coil shape shown in
FIG. 2, differing from that shown in FIG. 5.

[0036]FIG. 7 is a schematic sectional view extending along the tube axis
plane of the filaments formed by winding into the coil shape shown in
FIG. 2, differing from that shown in FIG. 5.

[0037]FIG. 8 is a view showing the configuration of a lamp unit configured
by disposing the lamp unit shown in FIG. 2, mutually in upper and lower
rows in a grid., in place of the configuration of the lamp unit shown in
FIG. 2.

[0038]FIG. 9 is a view showing the configuration of a lamp unit according
to the second embodiment.

[0039]FIG. 10 is a perspective view showing the configuration of the
filament lamp shown in FIG. 9.

[0040]FIG. 11 is a perspective view showing the configuration of a
filament lamp according to the third embodiment.

[0041]FIG. 12 is a view showing the configuration of a lamp unit applied
to the same type of apparatus as the light irradiation type heat
treatment device shown in FIG. 1, with the filament lamp shown in FIG. 11
applied as a lamp unit.

[0042]FIG. 13 is a view showing the configuration of a lamp unit 200
applied to a light irradiation type heat treatment device according to
conventional technology.

[0043]FIG. 14 is a view comparing spectral irradiance in a case in which
total irradiance is identical.

[0044]FIG. 15 is a view showing the absorbance properties (the
transmittance for light wavelength) at each wavelength for silicon (Si),
gallium arsenide (GaAs), and germanium (Ge).

DETAILED DESCRIPTION OF THE INVENTION

[0045]First, an embodiment of the present invention will be described
using FIGS. 1 through 8.

[0046]FIG. 1 is a frontal sectional view showing the configuration of a
light irradiation type heat treatment device according to a first
embodiment.

[0047]As shown in the drawings, a light irradiation type heat treatment
device 30 has a chamber 31 divided by a quartz window 32 into a lamp unit
holding space S1 and a thermal processing space S2. The chamber 31 is
made up of stainless steel or other metal material. Thermal processing is
performed by radiating light emitted from a lamp unit 40, disposed in the
lamp unit holding space S1, onto the article W to be treated that is
disposed in the thermal processing space S2.

[0048]Disposed above the lamp unit 40 is a reflective mirror 41. The
reflective mirror 41 has a structure of a main material of non-oxidized
copper coated with gold, for example, with a mirror image cross section
having a form with a circular portion, an elliptical portion, a parabolic
section, or a planar shape. The reflective mirror 41 is oriented upward
from the lamp unit 40 to reflect emitted light onto the article W to be
treated. In other words, in this apparatus 30, light emitted from the
lamp unit 40 is emitted directly or reflected via the reflective lamp 41
and is projected onto the article W to be treated.

[0049]Cooling air from a cooling air unit 45 is introduced into the lamp
unit holding space S1 from an outlet 46A of a cooling air supply nozzle
46 disposed in the chamber 31. The cooling air introduced into the lamp
unit holding space S1 blows onto each filament lamp 10 in the lamp unit
40, cooling the light emitting tubes that make up each filament lamp 10.
Here, the hermetically sealed portion of each filament lamp 10 has a low
heat resistance compared to other locations. As a result, it is
preferable to configure the apparatus so that the outlet 46A of the
cooling air supply nozzle 46 is disposed opposite the hermetically sealed
portion of each filament lamp 10 in order to preferentially cool the
hermetically sealed portion of each filament lamp 10.

[0050]The cooling air that has blown onto the filament lamps 10 and has
risen in temperature from heat exchange is discharged from a cooling air
discharge opening 47 disposed in the chamber 31. The flow of the cooling
air is designed so the cooling air that has been heated by heat exchange
will not conversely heat the filament lamps. In addition, the flow of the
cooling air is arranged to simultaneously cool the reflective mirror 41
as well. In a case in which the reflective mirror 41 is water cooled by a
chilled water mechanism (not shown), the flow of the cooling air need not
be arranged to simultaneously cool the reflective mirror 41.

[0051]If heat accumulation occurs in the quartz window 32 due to radiant
heat from the heated article W to be treated, an unwanted heating action
can occur in the article W to be treated due to thermal radiation emitted
secondarily from the quartz window 32 heated by irradiation. In this
case, heat controllability redundancy for the article W to be treated
(for example, an overshooting in which the temperature of the article to
be treated rises above the set temperature) and reduction in temperature
uniformity in the article W to be treated resulting from temperature
unevenness in the heated quartz window 32 itself occur. In addition,
increasing the speed of the temperature decline of the article W to be
treated becomes difficult. As a result, in order to prevent these
anomalies, it is preferable to dispose the outlet 46A of the cooling air
supply nozzle 46 in the proximity of the quartz window 32 so that the
quartz window 32 is cooled by cooling air from the cooling air unit 45,
as shown in FIG. 1.

[0052]Each filament lamp 10 in the lamp unit 50 is supported by a pair of
support frames 42A, 42B. The support frames 42A, 42B are made up of a
conductive plate 43 formed of an electrically conductive part and a
holding plate 44 formed of ceramic or another insulating member. The
holding plate 44 is disposed on the inner wall of the chamber 31 and
supports the conductive plate 43.

[0053]Disposed in the chamber 31 are a pair of power supply ports 36A, 36B
to which a power supply line is connected from a power supply apparatus
in a power unit 35. In FIG. 1, one grouping of the power supply ports
36A, 36B is shown, but the number of power supply ports 36 is determined
based on the number of filament lamps. The power supply ports 36A, 36B
are electrically connected to each conductive plate 43, which are
electrically connected to external leads of the filament lamps 10. By
configuring the apparatus in this manner, it is possible to supply power
from each power supply apparatus in the power unit 45 to each filament
lamp 10 in the lamp unit 40.

[0054]A processing plate 33 to which the article W to be treated is
attached is disposed in the thermal processing space S2. If the article W
to be treated is a semiconductor wafer, for example, the processing plate
33 is a thin-sheet circular object composed of molybdenum, tungsten,
tantalum or other high-melting point metal material along with a ceramic
material such as silicon carbide (SiC), or quartz or silicon (Si),
preferably with a guard ring structure on which is formed a step element
supporting the semiconductor wafer in the inner perimeter of a round
opening. The semiconductor wafer that is the article W to be treated is
disposed so the semiconductor wafer will fit into the round opening in
the circular guard ring, supported by the step element described above.
The processing plate 33 spontaneously rises in temperature due to
radiation emission, providing auxiliary radiant heating to the periphery
of the facing semiconductor wafer, supplementing heat radiation from the
peripheral edge of the semiconductor wafer. As a result, temperature drop
in the semiconductor wafer periphery due to thermal radiation from the
peripheral edge of the semiconductor wafer is inhibited.

[0055]A temperature measurement unit 51 is disposed in contact with or in
proximity to the article W to be treated on the side opposite the
radiation-receiving surface of the article W to be treated disposed on
the processing plate 33. The temperature measurement unit 51 is intended
to monitor the temperature distribution on the article W to be treated,
with the number and disposition of units determined by the dimensions of
the article W to be treated. A thermocouple or radiation thermometer, for
example, can be used as the temperature measurement unit 51. The
thermometer unit 51 transmits to a thermometer 50 observed temperature
information at predefined time intervals (once per second, for instance).
The thermometer 50 calculates the temperature at the spot measured by
each temperature measurement unit 51 based on the temperature information
transmitted from each temperature measurement unit 51, and sends the
calculated temperature information to a main control unit 55 via a
temperature control unit 52.

[0056]The main control unit 55 sends instructions to the temperature
control unit 52 based on temperature information obtained by the
thermometer 50 for each spot measured on the article W to be treated so
the temperature of the article W to be treated will be uniform at a
prescribed temperature. In addition, the temperature control unit 52
adjusts the electrical energy supplied to the filament lamp 10 based on
the instructions from the main control unit 55 so that the temperature of
the two zones Z1 and Z2 into which the article W to be treated is divided
will become uniform, as will be discussed hereafter.

[0057]FIG. 2 shows a view from above of the configuration of the lamp unit
40 shown in FIG. 1. FIG. 3 shows a perspective view of the configuration
of the filament lamp 10 shown in FIG. 2. FIGS. 4(a) & 4(b) shows a
cutaway view, along a plane running through the tube axis, of the
filament strand of the filament 20 formed in a coil shape as shown in
FIG. 3.

[0058]As shown in FIG. 3, the filament lamp 10 has a light emitting tube
22 composed of glass material, for instance, upon which are formed
hermetically sealed portions 21A and 21B on both ends. The interior space
of the light emitting tube 22 is injected with halogen gas, for example.
The coil-shaped filaments 20 formed by wrapping filament strands of
tungsten, for example, into a coil shape are disposed extending along the
tube axis of the light emitting tube 22. Formed on each end are leads
23A, 23B, connected via metal foils 24A, 24B to external leads 25A, 25B.

[0059]In addition, when light from the filament strands is emitted
externally from the filament strands as shown in FIG. 4(a), the light is
described as the sum of that light and light emitted from those filament
strands through the adjacent space between filament strands (angles
θ1, θ2, θ3, . . . as viewed from the filament strands)
FIG. 4(b).

[0060]As shown in FIG. 2, the lamp unit 40 is configured with 9 filament
lamps 10, for example, disposed in a row at a prescribed distance apart
(for instance, 15 mm) on the same plane as the lamp center axis. The end
in the center axis direction of each filament 20 in each filament lamp 10
is disposed extending above the imaginary circle 400 on the outside of
the periphery of the article W to be treated, configured so that the
total length mutually differs in the center axis direction. Specifically,
since the 9 filaments 20 possessed by the 9 filament lamps 10, the
filaments having different total lengths in the center axis direction,
are disposed in a row on the same plane at a prescribed distance apart, a
concentric circular surface light source is constituted with the article
W to be treated.

[0061]When the article W to be treated is thermally processed, the article
W to be treated is divided into 2 zones, for example: a peripheral zone
Z1 and a center zone Z2. Illumination control of each filament lamp 10 is
performed so as to obtain a prescribed temperature distribution for each
zone Z1, Z2. In order to carry out this temperature distribution control
on the article W to be treated, the lamp unit 40 is configured with a
lamp group G1, formed of a plurality of filament lamps 10 disposed across
the peripheral zone Z1 and the center zone Z2 of the article W to be
treated, and lamp groups G2, G3, formed of respective pluralities of
filament lamps 10 disposed on both sides of the lamp group G1.

[0062]The apparatus is configured so that the effective surface area S per
unit of length for each of the filaments F1 in each of the filament lamps
belonging to the lamp groups G2, G3 is larger than the effective surface
area S per unit of length in each of the filaments F2 in each of the
filament lamps 10 belonging to the lamp group G1. The effective surface
area S is the value of the surface area per unit of length observable
from the outside of the filament in the center axis direction of the
filament 20. In other words, the effective surface area S is the area of
the surface contributing to the light emitted to the outside from the
filament 20 without being shielded by the filament itself, relative to
the total surface area of the filaments 20 (this point will be discussed
in detail hereafter). Here, the effective surface area of the filaments
F1 is increased in relation to the effective surface area of the
filaments F2 for the following reason.

[0063]As discussed previously, in order to perform rapid thermal
processing on the article W to be treated with uniform temperature
distribution on the surface of the article W to be treated, the intensity
of the light emitted onto the peripheral zone Z1 of the article W to be
treated must be increased relative to that of the center zone Z2.
However, as discussed above, conventionally this need has been addressed
by making the rated power density of each filament F1 disposed facing the
peripheral zone Z1 of the article W to be treated identical, by making
the rated power density of each filament F2 disposed facing the center
edge zone Z2 of the article W to be treated identical, and by making the
rated power density of each filament F1 greater than that of each
filament F2. However, since a temperature differential occurs between
zone Z1 and zone Z2, an anomaly occurs so that heating the article W to
be treated with a uniform temperature distribution on the surface of the
article W to be treated is impossible. The present invention is based
upon having obtained the knowledge that the emission intensity of light
emitted by the filaments 20 is dependent upon a completely different
cause from the rated power density, as shown in equation 1 and equation 2
below.

[0064]In other words, as shown in equation 1, the emission intensity E per
unit of length from the filaments is determined principally by two
causes: the effective surface area S of the filaments, and the color
temperature T of the filaments when the filament lamp is operated.
ε in equation 1 is obtained from a fixed value dependent on the
material. σ is the Stefan-Boltzmann constant (5.6697*10-8
W/m2*K). Consequently, in equation 1, if the filament color
temperature is kept constant, the emission intensity E from the filaments
is proportional to the effective surface area S of the filaments.

E=S*ε*σ*T4 (Equation 1)

[0065]When the wavelength-specific emission intensity is applied using a
Planck distribution equation:

B(λ)=(2hc2/λ5)*(1/(ehc/λkT-1))
(Equation 2)

B (λ) is the emission intensity of a black body at wavelength
λ, λ is the wavelength, h is the Planck constant, c is the
speed of light, and k is the Boltzmann constant.

[0066]In other words, in the lamp unit 40, by making the temperature of
all the filaments 20 belonging to the same zone uniform, that is, by
making the color temperature of the light emitted from the filaments 20
uniform, and by having the effective surface areas SF1 and SF2
of each of the filaments F1, F2 satisfy the relationship shown below, the
emission intensity EF1 emitted from each of the filaments F1 can be
increased relative to the emission intensity EF2 emitted from each
of the filaments F2, and the shape of the emission spectrum in each of
the filaments F1 can be made identical to the shape of the emission
spectrum in each of the filaments F2 (see, FIG. 14).

(Relationship 1)

[0067]Effective surface area SF1 of each filament F1>effective
surface area SF2 of each filament F2

[0068]In order to make the color temperature of the filaments F1 identical
to the color temperature of the filaments F2 in the lamp unit 40, the
rated power density for the filaments F1 and F2 should be set to satisfy
relationship 2 shown below, since the emission intensity in equation 1
above has essentially the same value as the rated power density applied
to the filaments.

(Relationship 2)

[0069]Rated power density MF1 of the filaments F1>rated power
density MF2 of the filaments F2
[0070]MF1/MF2=SF1/SF2

[0071]Here, the values of the effective surface areas SF1, SF2
are determined based on equation 3 and equation 4 below.

S=2πRL*K (Equation 3)

R is the radius of the filament strand, and L is the total length of the
filament strand.

K=180°/360°+(θ1+θ2+ . . . +θn)/180°
(Equation 4)

See, FIG. 4(b) regarding θ1, θ2 . . .

[0072]Equation 3 gives the effective surface area per unit of length of
the filaments configured with the filament strands wound into a coil
shape. The effective surface area S of the filaments is determined by
multiplying 2πRL, representing the surface area of filament strands
with a round cross-sectional area in the radial direction by the
coefficient K that is given by Equation 4.

[0073]Equation 4 gives the total sum of the proportion of light emitted
from filament strands disposed on the outside of the filament coil and
the proportion of light emitted from filament strands disposed on the
inside of the filament coil. Described in greater detail, the first half
of Equation 4 represents the proportion of light emitted from filament
strands disposed on the outside of the filament coil, while the latter
half of Equation 4 represents the proportion of light emitted to the
outside of the filaments without being shielded by filament strands
disposed in the light progression direction.

[0074]FIG. 5 is a sectional view of a plane along the tube axis of the
filaments F1, F2 wound into a coil shape as in FIG. 2.

[0075]As discussed in connection with Relationship 1, the effective
surface area SF1 of each filament F1 is configured so as to be
greater than the effective surface area SF2 of each filament F2. As
a result, as shown in FIG. 5, the outer coil diameter of each filament F1
is increased in relation to the outer coil diameter of each filament F2.
Here, the phrase "outer coil diameter" refers to the distance between 2
parallel lines when the outer edge of the filament is bisected by 2
parallel lines in a section portioning the filament on a center plane
including the center axis of the filament.

[0076]Specifically, if DF1 represents the outer coil diameter of the
filaments F1 and the outer coil diameter of the filaments F2 is
represented by DF2, it is preferable to configure the filaments F1
and the filaments F2 to satisfy the relationship DF1/DF2=1.53
to 2.45. If the value falls below this range, anomalies will occur in
that it will be impossible to obtain the desired surface area, the input
power will be insufficient, and the temperature at the wafer edge will
fall. Also, if the value rises above this range, the outer coil diameter
DF1 of the filaments F1 will be too large, the filaments will be too
heavy, and the filament strands will be unable to bear the weight,
resulting in coil deformation and having an adverse effect on uniformity
of level of illumination. Furthermore, if the value is extremely large,
deformation will result in short-circuiting between coils and coil
breakage.

[0077]In a light irradiation type heat treatment device having a lamp unit
40 configured in this manner, the filament lamps 10 in the lamp unit 40
are illuminated while the article W to be treated is rotated in a
circular direction by a prescribed means. The reason for rotating the
article W to be treated is to render the temperature identical in the
locations of the zone F1 of the article W to be treated facing the
filaments F1 and in the locations of the zone F2 of the article W to be
treated facing the filaments F2. By configuring the apparatus in this
manner, it is possible to increase the emission intensity EF1 from
the filaments F1 relative to the emission intensity EF2 of the
filaments F2, and to make the emission spectrum shape in the filaments F1
identical to the emission spectrum shape in the filaments F2 (see FIG.
14). Accordingly, it is possible to heat the article W to be treated with
uniform temperature distribution of the entire surface of the article W
to be treated.

[0078]Furthermore, in this light irradiation type heat treatment device,
by making the effective surface area of each filament F1 identical, and
making the effective surface area of each filament F2 identical, the
irradiance per unit of surface area emitted onto each of the zones Z1, Z2
becomes identical, as shown in Relationship 3 below, thereby making it
possible to heat the article W to be treated with an even more uniform
temperature distribution on the article W to be treated.

(Relationship 3)

[0079]Effective surface area of filaments F1 is identical for each.
[0080]Effective surface area of filaments F2 is identical for each.

[0081]Based on the following circumstances, it is believed to be even more
preferable for the light irradiation type heat treatment device to
satisfy relationship 3 above. In other words, the light irradiation type
heat treatment device is designed with differing respective outer coil
diameters, coil pitches, and coil strand diameters so that each of the
filaments disposed corresponding to each zone have differing lengths
while having the same rated power density. As a result, different
filaments F2 disposed facing the center zone Z2 of the article W to be
treated have slight individual differences in effective surface area, and
slight individual differences in color temperature as a result.
Accordingly, it may be conjectured that the emission intensity E emitted
from each of the filaments F2 will differ slightly. In this case, as
shown in FIG. 13, for example, it may be conjectured that in the zone Z1,
an area X in which the temperature of the article to be treated is
relatively high and an area Y in which the temperature is relatively low
will be formed locally, although the differences will only be slight,
resulting in a slight loss of uniform temperature distribution on the
surface of the article W to be treated.

[0082]Consequently, in a case in which strict consistency of surface
temperature is required for the article to be treated, the effective
surface area S of the filaments F1 facing the peripheral zone Z1 should
be equalized, and the effective surface area S of the filaments F2 facing
the center zone Z2 should be equalized, as shown in Relationship 3 above.
Of course, if strict consistency of surface temperature for the article
to be treated is not required, there is no need to satisfy Relationship
3.

[0083]FIGS. 6 & 7 are sectional views taken along a plane including the
tube axis of the filaments 20 formed by winding into a coil shape in FIG.
3, unlike the embodiment shown in FIG. 5. These drawings compare the
filaments F1 and the filaments F2 shown in FIG. 2.

[0084]In FIG. 6, the filaments F1 and the filaments F2 are configured so
that the coil pitch of the filaments F1 is smaller than the coil pitch of
the filaments F2. But even when configured in this manner, it is still
possible to increase the effective surface area SF1 of the filaments
F1 in relation to the effective surface area SF2 of the filaments
F2.

[0085]Here, the phrase "coil pitch" refers to the distance of a line
between the respective center points of two adjacent filament strands in
a section in which the filament is portioned into a flat plane including
the filament center axis.

[0086]Specifically, when the coil pitch of each filament F1 is represented
as PF1 and the coil pitch of each filament F2 is represented as
PF2, it is preferable to configure the filaments F1 and the
filaments F2 to satisfy the relationship PF1/PF2=0.5 to 0.85.
If the value falls below this range, the distance between the coil loops
becomes too small, resulting in short circuiting and breakage. If the
value rises above this range, it becomes impossible to obtain the desired
surface area, the input power is insufficient, and the temperature at the
wafer edge will fall.

[0087]In FIG. 7, the filaments F1 and the filaments F2 are configured so
that the outer diameter of the filament strands of the filaments F1 is
greater than the outer diameter of the filament strands of the filaments
F2. However, even when configured in this manner, it is still possible to
increase the effective surface area of the filaments F1 in relation to
the effective surface area of the filaments F2.

[0088]Here, the phrase "outer diameter of the filament strands" refers to
the distance between two parallel lines when the outer edge of a filament
strand is tangent to two parallel lines, in a section in which the
filament is portioned into a flat plane including the filament center
axis.

[0089]Specifically, when the outer diameter of a filament strand in each
filament F1 is represented as φF1 and the outer diameter of a
filament strand in each filament F2 is represented as φF2, it is
preferable to configure the filaments F1 and the filaments F2 to satisfy
the relationship φF1/φF2=1.07 to 1.30. If the value
falls below this range, it becomes impossible to obtain the desired
surface area, the input power is insufficient, and the temperature at the
wafer edge will fall. If the value rises above this range, the gap
between the coil strands becomes too small, resulting in short-circuiting
and breakage.

[0090]FIG. 8 shows the configuration of a lamp unit 60 configured with the
lamp units 40 shown in FIG. 2 disposed in a grid with upper and lower
rows, in place of the configuration of the lamp units 40 shown in FIG. 2.

[0091]In the lamp unit 40 shown in FIG. 2, the lamp unit 40 has a
plurality of filament lamps 10 disposed in a row so that the tube axis of
each filament lamp 10 is located on the same plane. The lamp unit 40 is
used to heat the article W to be treated with uniform temperature by
radiation from each filament lamp onto the article W to be treated, with
the article W to be treated rotated in a circular direction. In contrast,
in the lamp unit 60 shown in FIG. 8, it is possible to heat the article W
to be treated with uniform temperature without rotating the article W to
be treated.

[0092]In other words, in the lamp unit 60 shown in FIG. 8, the apparatus
is configured so that above (on the opposite side of the article W to be
treated) a first surface light source 60A, in which a plurality of
filament lamps 10 is arranged so the tube axis of each filament lamp 10
is disposed on the same plane, is arranged a second surface light source
60B, in which a plurality of filament lamps 10' are arranged so the tube
axis of each filament lamp 10' is disposed on the same plane and the tube
axis of each filament lamp 10' bisects the tube axis of each filament
lamp 10 at right angles. In other words, the lamp unit 60 is configured
with the plurality of filament lamps 10, 10' disposed in a so-called grid
pattern. Also, the ends in the center axis direction of each filament in
each of the filament lamps 10, 10' are disposed to extend over the
outside of the imaginary circle 600 on the peripheral edge of the article
W to be treated, and are configured with differing total lengths in the
center axis direction.

[0093]The first surface light source 60A is configured so that the
effective surface area SF1 of the filaments F1 facing only the
peripheral zone Z1 of the article W to be treated is greater than the
effective surface area SF2 of the filaments F2 facing both the
peripheral zone Z1 and the center zone Z2 of the article W to be treated.
The second surface light source 60B is configured so that the effective
surface area SF1' of the filaments F1' facing only the peripheral
zone Z1 of the article W to be treated is greater than the effective
surface area SF2' of the filaments F2' facing both the peripheral
zone Z1 and the center zone Z2 of the article W to be treated. Note that
the apparatus is configured so that the effective surface area SF1
of the filaments F1 is identical to the effective surface area SF1'
of the filaments F1'. Similarly, the apparatus is configured so that the
effective surface area SF2 of the filaments F2 is identical to the
effective surface area SF2' of the filaments F2'.

[0094]In the lamp unit 60 shown in FIG. 8, the effective surface area and
the rated power density for each filament are set to satisfy
relationships 1 and 2 above. By operating all the filament lamps 10, 10'
belonging to the lamp unit 60 with the same color temperature for each
filament, it is possible to increase the irradiance per unit of surface
area emitted onto the zone Z1 in relation to the irradiance per unit of
surface area emitted onto the zone Z2, and it is possible to render
identical the shape of the emission spectrum for each filament. As a
result, it is possible to heat the article W to be treated with uniform
temperature distribution on the surface of the article W to be treated.
Furthermore, if the effective surface areas of each of the filaments F1,
F1' are made identical, and if the effective surface areas of each of the
filaments F2, F2' are made identical, it is possible to make the
irradiance per unit of surface area emitted onto each of the zones Z1, Z2
identical for each of the zones Z1, Z2.

[0095]Next, a second embodiment of the present invention will be described
with reference to FIGS. 9 & 10.

[0096]FIG. 9 shows the configuration of a lamp unit 70 applied to the same
type of apparatus as the light irradiation type heat treatment device
shown in FIG. 1, but having a different configuration from the lamp unit
40 shown in FIG. 2. FIG. 10 shows a perspective view of the configuration
of the filament lamp 100 shown in FIG. 9.

[0097]As shown in FIG. 9, the lamp unit 70 is configured with a lamp group
G1 having a plurality of filament lamps 100 disposed facing both the
peripheral zone Z1 of the article W to be treated and the center zone Z2
of the article W to be treated, and lamp groups G2, G3 having a plurality
of filament lamps 10 disposed on both sides of the lamp group G1 and
facing only the peripheral areas of the article W to be treated. Here,
the ends in the center axis direction of each of the filaments 20, 110 of
the filament lamps 10, 100 are disposed extending over an imaginary
circle 700 on the outside of the peripheral of the article W to be
treated, configured with differing total lengths in the center axis
direction.

[0098]As shown in FIG. 10, the filament lamps 100 belonging to the lamp
group G1 have the same configuration as the filament lamps 10 shown in
FIG. 3, except for having different filament configurations. In other
words, the coil-shaped filaments 110 disposed inside the light emitting
tube 102 of the filament lamps 100 are configured with central filaments
F2'', each of which disposed in the center between a respective pair of
end filaments F1'' which extend from a respective end of the central
filaments F2'' and are formed with a larger outer coil diameter than the
central filaments F2''. Furthermore, filaments F1'' are configured so
that the effective surface area SF1'' per unit of length of the end
filaments F1'' is greater than the effective surface area SF2'' per
unit of length of the central filaments F2''. Connected to the ends of
each of the end filaments F1'' are leads 103A, 103B connected to
respective metal foils 104A, 104B. The filaments 110 are formed by
connecting one end of each of the end filaments F1'' to both ends of the
central filaments F2'', by a weld spot that is not a light emitting
element. Here, the filaments F2'' disposed in the center in the tube axis
direction are low-emission coils, while the end filaments F1'' disposed
on the edges are high emission coils.

[0099]As shown in FIG. 9, in the lamp group G1 having a plurality of
filament lamps 100, the end filaments F1'' are disposed facing the
peripheral zone Z1 of the article W to be treated, and the central
filaments F2'' are disposed facing the center zone Z2 of the article W to
be treated.

[0100]For their part, the filament lamps 10 of the lamp groups G2, G3
facing the peripheral zone Z1 of the article W to be treated have the
same configuration as the filament lamps shown in FIG. 3. The effective
surface area SF1 per unit of length in the filaments F1 of the
filament lamps 10 is the same as the effective surface SF1'' of the
end filaments F1'', and is greater than the effective surface area
SF2'' per unit of area of the central filaments F2''.

[0101]According to this lamp unit 70, the effective surface area and the
rated power density of each filament are set so as to satisfy
relationships 1 and 2 above. As a result, all of the filament lamps 10,
100 belonging to the lamp unit 70 are operated so the color temperature
of the filaments is uniform. If the article W to be treated is heated
using this lamp unit 70, there is no need to rotate the article W to be
treated.

[0102]According to this lamp unit 70, directly below the lamp unit 70, the
irradiance per unit of surface area emitted onto the peripheral zone Z1
of the article W to be treated can be made greater than the irradiance
per unit of surface area emitted onto the center zone Z2 of the article W
to be treated, and the form of the emission spectrum for each filament
can be rendered identical (see, FIG. 14). Accordingly, it is possible to
heat the article W to be treated with a uniform temperature distribution
on the surface of the article W to be treated. Furthermore, if the
effective surface areas of the filaments F1, F1'' are made identical and
the effective surface areas of the filaments F2, F2'' are made identical,
as shown in relationship 3 above, it is possible to make the irradiance
per unit of surface area emitted onto each of the zones Z1, Z2 identical
for each of the zones Z1, Z2.

[0103]Next, a third embodiment of the present invention will be described
using FIGS. 11 & 12.

[0104]FIG. 11 is a perspective view showing the configuration of a
filament lamp 120 according to the present embodiment. FIG. 12 shows the
configuration of a lamp unit 80 to which the filament lamp 120 shown in
FIG. 11 is applied as a lamp unit.

[0105]The filament lamp 120 shown in FIG. 11 has a configuration in which
a plurality of filament assemblies having a filament 130 formed into a
coil shape and a pair of leads 112A, 112B connected to both ends of the
filament are arranged so that the filaments 130 extend sequentially along
the tube axis of a light emitting tube 112. On both ends of the light
emitting tube 112 are formed hermetically sealed portions 111A, 111B
creating an airtight seal by bonding sealing insulators 115A, 115B
disposed in the interior of the light emitting tube 112 and the interior
surface of the light emitting tube 112 using metal foils 113A, 113B
arranged at an appropriate distance apart on the perimeter surface of the
sealing insulators 115A, 115B and a number of units double that of the
number of filament assemblies. On one end of the metal foils 113A, 113B
are connected internal leads 112A. 112B, and on the other end of the
metal foils 113A, 113B are connected external leads 114A, 114B, extending
from the outer edge surface of the light emitting tube 112 to the
exterior and reaching a power supply apparatus not shown in the drawing.
As a result, power is supplied from the power supply apparatus to the
filament assemblies via the external leads 114A, 114B, the metal foils
113A, 113B, and the internal leads 112A, 112B. In this filament lamp 120,
it is possible to supply power independently to each filament 130.

[0106]In this filament lamp 120, the effective surface area of the
filaments F1'' disposed at the ends in the tube axis direction is greater
than the effective surface area of the filaments F2'' disposed in the
center in the tube axis direction of the light emitting tube 112. In
other words, as shown in FIGS. 5-7, the coil outer diameter of the
filaments F1, F1'' is made larger than the coil outer diameter of the
filaments F2'', the coil pitch of the filaments F1, F1'' is made smaller
than the coil pitch of the filaments F2'', and the coil strand diameter
of the filaments F1, F1'' is made larger than the coil strand diameter of
the filaments F2''. Here, the filaments F2'' disposed in the center in
the tube axis direction are low emission filaments, while the filaments
F1'' disposed on the edges are high emission filaments.

[0107]The lamp unit 80 shown in FIG. 12 is configured with two units that
each comprise the filament lamps 10 with the configuration shown in FIG.
3 and are disposed on both sides of the 5 filament lamps 120 having the
configuration shown in FIG. 11, with the tube axes of the filament lamps
10, 120 arranged a prescribed distance apart (15 mm, for instance) on the
same plane. Specifically, the filament lamps 10 having the configuration
shown in FIG. 3 are arranged corresponding to the peripheral zone Z1 of
the article W to be treated, while the filament 120 having a
configuration in which a plurality of filaments is disposed inside a
light emitting tube are arranged corresponding to the peripheral zone Z1
and the center zone Z2 of the article W to be treated.

[0108]According to this lamp unit 80, the filament lamps 120 and the
filament lamps 10 are arranged in relation to the article W to be treated
as described below. In other words, the filament lamps 120 are arranged
with the filaments F2'' disposed in the center in the tube axis direction
corresponding to the center zone Z2 of the article W to be treated, and
with the filaments F1'' disposed on both ends of the filaments F2'' in
the tube axis direction corresponding to the zone Z1 of the article W to
be treated. The filament lamps 10 are arranged with the filaments 20
(treated as filaments F1) corresponding to the zone Z1 of the article W
to be treated.

[0109]The filaments F2'' of the filament lamps 120 have differing total
lengths in the tube axis direction, while the imaginary circle 801 formed
connecting the ends in the tube direction of the filaments F2'' is
arranged in relation to the article W to be treated to match the exterior
edge of the center zone Z2 of the article W to be treated. In addition,
the filaments F1'' of the filament lamps 120 and the filaments F1 of the
filament lamps 10 have differing total lengths in the tube axis
direction, and are arranged so that one end of each filament F1'' is
disposed on the outer edge of an imaginary circle 801 and the other end
is disposed on the outer edge of an imaginary circle 802 formed on the
outside of the peripheral of the article W to be treated, with both ends
of the filaments F1 arranged on the outer edge of the imaginary circle
802.

[0110]In addition, in the filaments of the filament lamp 120 that comprise
the lamp unit 80, as shown in FIGS. 5-7, the coil outer diameter of the
filaments F1, F1'' is made larger than the coil outer diameter of the
filaments F2'', the coil pitch of the filaments F1, F1'' is made smaller
than the coil pitch of the filaments F2'', and the coil strand diameter
of the filaments F1, F1'' is made larger than the coil strand diameter of
the filaments F2''.

[0111]According to this lamp unit 80, the effective surface area and the
rated power density of each filament are set so as to satisfy
relationships 1 and 2 above. All of the filament lamps 10, 100 belonging
to the lamp unit 80 are operated so the color temperature of the
filaments is uniform. If the article W to be treated is heated using this
lamp unit 80, there is no need to rotate the article W to be treated.

[0112]Therefore, in the light irradiation type heat treatment device
according to the present embodiment, directly below the lamp unit 80, the
irradiance per unit of surface area emitted onto the peripheral zone Z1
of the article W to be treated can be made greater than the irradiance
per unit of surface area emitted onto the center zone Z2 of the article W
to be treated, and the form of the emission spectrum for each filament
can be rendered identical (see, FIG. 14). Accordingly, it is possible to
heat the article W to be treated with a uniform temperature distribution
on the surface of the article W to be treated. Furthermore, if the
effective surface areas of the filaments F1, F1'' are made identical and
the effective surface areas of the filaments F2, F2'' are made identical,
as shown in relationship 3 above, it is possible to make the irradiance
per unit of surface area emitted onto each of the zones Z1, Z2 identical
for each of the zones Z1, Z2.